Mortality patterns reflect fundamental characteristics of societies and help to reveal important changes in population health over time. In order to improve our understanding of such topics, we propose here to examine historical and contemporary mortality patterns for a wide range of industrialized countries, including the United States. The work for this project is organized into three parts. The first part consists of an analysis of past trends in both total and cause-specific mortality. The second part addresses fundamental issues about how best to project mortality trends into the future. In the third part of the project, we will continue to build and improve the Human Mortality Database (HMD; http://www.mortality.org). The substantive questions that motivate this project are focused on certain features of recent mortality trends sharing two key characteristics: 1) they represent important breaks with the past, and 2) they introduce a significant element of uncertainty with regard to future trends. Specifically, we will examine the pronounced slowdown in the pace of mortality reduction at advanced ages in the United States since the early 1980s. This trend has affected female mortality in particular, contributing to an overall narrowing of sex differences. We propose to review the long-term evolution of the sex gap in mortality as background for an analysis of recent trends. To enrich these studies, the project includes a specific component for the collection and analysis of historical mortality data by cause of death. The methodology of mortality projection forms the second part of the proposed project. The accuracy of alternative approaches will be assessed by various means with respect to certain key features: for example, whether it is better to derive projections of total mortality from separate projections by sex and/or cause of death. Lastly, both the substantive and methodological parts of this project will be aided by our continuing efforts to develop the Human Mortality Database, which is used widely by other researchers as well. [unreadable] [unreadable]